Which graph represents the piecewise defined function y={-4 if x<-3 0 if x =2 3 if x>2

Total no. of students - 140 students
Total no. of students from all schools= 140+70+35+105=350
school A= 140÷350×100=40./. (multiplying by 100 because it's the total percentage )
School B = 70÷350×100=20./.
School C = 105÷350×100=30./.
School D = 105÷350×100= 10./.
Consisting all the schools percentage it gives 100./.

Hope this helps